1. Field of the Invention
This invention relates to a two part silicone sealant which cures upon mixing of the two parts to give an ultra low modulus elastomeric sealant.
2. Background Information
British Patent Specification 1,308,985, published Mar. 7, 1983, discloses a method of curing room temperature vulcanizing silicone rubber containing acetoxy-silicon bonds, which method adds sodium alumino silicate having adsorbed water. The water from the aluminosilicate causes the silicone rubber to cure even if the composition is not open to atmospheric moisture.
A silicone composition which cures upon exposure to moisture in the air is described in U.S. Pat. No. 3,817,909, issued Jun. 18, 1974. This composition is obtained by mixing a hydroxyl endblocked polydiorganosiloxane, non-acidic, non-reinforcing filler, a difunctional acetamidosilane, and an aminoxysilicon compound.
An organopolysiloxane composition which rapidly hardens to the elastomeric state is disclosed in U.S. Pat. No. 4,508,888, issued Apr. 2, 1985. The composition comprises a polyhydroxylated polysiloxane, a polyacyloxysilane cross-linking agent, and a hardening accelerator comprising water and an alkali or alkaline earth metal phosphate and/or polyphosphate.